Impedance Control and Performance Measure of Series Elastic Actuators
| Autor: | Steven Jens Jorgensen, Luis Sentis, Nicholas Paine, Ye Zhao |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0209 industrial biotechnology
Engineering business.industry 020208 electrical & electronic engineering Automatic frequency control Impedance bridging 02 engineering and technology Feedback loop 020901 industrial engineering & automation Impedance control Control and Systems Engineering Control theory 0202 electrical engineering electronic engineering information engineering Electronic engineering Torque Electrical and Electronic Engineering business Performance metric Electrical impedance |
| Zdroj: | IEEE Transactions on Industrial Electronics. 65:2817-2827 |
| ISSN: | 1557-9948 0278-0046 |
| DOI: | 10.1109/tie.2017.2745407 |
| Popis: | Series elastic actuators (SEAs) have become prevalent in torque-controlled robots in recent years to achieve compliant interactions with environments and humans. However, designing optimal impedance controllers and characterizing impedance performance for SEAs with time delays and filtering are still underexplored problems. This article addresses the controller design problem by devising a critically damped gain design method for a class of SEA cascaded control architectures, which is composed of outer impedance and inner torque feedback loops. We indicate that the proposed gain design criterion solves optimal controller gains by maximizing phase-margin-based stability. Meanwhile, we observe a tradeoff between impedance and torque controller gains and analyze their interdependence in terms of closed-loop stability and overall impedance performance. Via the proposed controller design criterion, we adopt frequency-domain methods to thoroughly analyze the effects of time delays, filtering, and load inertia on SEA impedance performance. A novel impedance performance metric, defined as “Z-region,” is proposed to simultaneously quantify achievable impedance magnitude range (i.e., Z-width) and frequency range (i.e., Z-depth). Maximizing the Z-region enables SEA-equipped robots to achieve a wide variety of Cartesian impedance tasks without alternating the control structure. Simulations and experimental implementations are performed to validate the proposed method and performance metric. |
| Databáze: | OpenAIRE |
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